1. Field of the Invention
Embodiments of the present invention generally relate to an apparatus and method for controlling radiation from an aperture.
2. Description of the Related Art
To match the constant demand for smaller and more powerful devices, the size of integrated components on semiconductors has decreased. As features on semiconductor devices become smaller, higher resolution is needed for light used in processes such as photolithography and thermal processing. Radiation uniformity and control are critical capabilities of any photolithography or radiation thermal processing system used for semiconductor applications.
Advanced anneal devices use apertures to process one field at a time. The aperture is imaged on the wafer and only the transmissive area of the aperture is processed. Instead of processing the full field, one can mask or block some areas where process is not needed or desired.
As light comes in contact with an obstacle, such as the edge of an aperture or the edge of a lithographic mask, the light can be diffracted by the obstacle. The diffraction of the light can create edges, round corners or other effects in the exposed photoresist or annealed section which did not exist in the design of the aperture or mask.
Optical Proximity Correction (OPC) has been used to accommodate for the expected distortions of the light created by known obstacles in photolithography. This may be driven by pre-computed look-up tables based on width and spacing between features (rule based OPC) or by using compact models to dynamically simulate the final pattern and thereby drive the movement of edges, typically broken into sections, to find the best solution (model based OPC).
As features become more compact, radiation uniformity and control in optical thermal processing must be increased to accommodate. Current systems are able to achieve non-uniformity of approximately 3%. However, further improvement is needed as demands on manufacturing capabilities continue to increase.
Thus, there is a need in the art for methods and apparatus which allow for increased non-uniformity and thereby increased throughput in optics based semiconductor processing.